Quantum Coherent Atomic Tunneling between Two Trapped Bose-Einstein Condensates

We study the coherent atomic tunneling between two zero-temperature-Einstein condensates (BEC) confined in a double-well magnetic trap. Two-Pitaevskii equations for the self-interacting BEC amplitudes, coupled by transfer matrix element, describe the dynamics in terms of the inter-well-difference and population imbalance. In addition to the anharmonic of the familiar ac Josephson effect and plasma oscillations in superconductor junctions, the non-linear BEC tunneling dynamics a self-maintained population imbalance: a novel "macroscopic quantum-trapping effect".